/* roulang page: index */
:root {
      --ember: #C2410C;
      --ember-hover: #9A3412;
      --steel: #3F4F46;
      --gold: #D4A017;
      --paper: #FAF7F2;
      --smoke: #F1EBE3;
      --char: #1C1917;
      --ink: #292524;
      --muted: #57534E;
      --inverse: #F5F5F4;
      --line: #E7E0D6;
      --radius: 8px;
      --radius-sm: 6px;
      --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.06);
      --shadow-hover: 0 8px 24px rgb(28 25 23 / 0.08);
      --container: 1240px;
      --gutter: 24px;
      --topbar-h: 40px;
      --nav-h: 80px;
      --header-h: 120px;
      --focus: 2px solid #3F4F46;
    }
    *, *::before, *::after { box-sizing: border-box; }
    html { scroll-behavior: smooth; }
    body {
      margin: 0;
      font-family: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", Inter, ui-sans-serif, system-ui, sans-serif;
      color: var(--ink);
      background: var(--paper);
      font-size: 16px;
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
    }
    img { max-width: 100%; height: auto; display: block; }
    a { color: inherit; text-decoration: none; }
    button, input, select, textarea { font-family: inherit; }
    button { cursor: pointer; }
    h1, h2, h3, h4, p { margin: 0; }
    ul { margin: 0; padding: 0; list-style: none; }
    :focus-visible { outline: var(--focus); outline-offset: 3px; }
    .container {
      width: min(100% - 40px, var(--container));
      margin-inline: auto;
    }
    .skip-link {
      position: absolute; left: -999px; top: 8px; z-index: 100;
      background: var(--ember); color: #fff; padding: 8px 14px; border-radius: var(--radius-sm);
    }
    .skip-link:focus { left: 12px; }
    .topbar {
      height: var(--topbar-h);
      background: var(--char);
      color: #A8A29A;
      font-size: 12.5px;
      line-height: var(--topbar-h);
    }
    .topbar .container {
      display: flex; justify-content: space-between; align-items: center; gap: 16px;
    }
    .topbar a { color: #D6D3D1; }
    .topbar a:hover { color: var(--gold); }
    .topbar-right { display: flex; gap: 20px; align-items: center; }
    .site-header { background: #FFFcf8; border-bottom: 1px solid var(--line); }
    .site-header.is-stuck .nav-main { position: sticky; }
    .nav-main {
      height: var(--nav-h);
      display: flex; align-items: center;
      transition: height .2s ease;
    }
    .site-header.is-stuck .nav-main { height: 64px; }
    .nav-inner {
      display: flex; align-items: center; justify-content: space-between; gap: 20px; width: 100%;
    }
    .logo {
      display: flex; align-items: center; gap: 10px; flex-shrink: 0; font-weight: 700; letter-spacing: -.02em;
      color: var(--char); font-size: 18px;
    }
    .logo-mark {
      width: 36px; height: 36px; display: grid; place-items: center;
    }
    .nav-links { display: flex; align-items: center; gap: 4px; }
    .nav-links a {
      position: relative; padding: 10px 12px; font-size: 15px; font-weight: 500; color: var(--steel);
    }
    .nav-links a:hover { color: var(--ember); }
    .nav-links a.active { color: var(--ember); }
    .nav-links a.active::after,
    .nav-links a:hover::after {
      content: ""; position: absolute; left: 12px; right: 12px; bottom: 4px; height: 2px; background: var(--ember);
    }
    .btn {
      display: inline-flex; align-items: center; justify-content: center; gap: 8px;
      min-height: 46px; padding: 0 22px; border-radius: var(--radius-sm);
      font-weight: 600; font-size: 15px; border: 1.5px solid transparent;
      transition: background .2s, transform .2s, border-color .2s, color .2s;
    }
    .btn:hover { transform: translateY(-1px); }
    .btn:active { transform: translateY(0); }
    .btn-primary { background: var(--ember); color: #fff; }
    .btn-primary:hover { background: var(--ember-hover); }
    .btn-ghost {
      background: transparent; color: #fff; border-color: rgba(245,245,244,.55);
    }
    .btn-ghost:hover { border-color: #fff; background: rgb(255 255 255 / .08); }
    .btn-steel {
      background: transparent; color: var(--steel); border-color: var(--steel);
    }
    .btn-steel:hover { background: var(--steel); color: #fff; }
    .nav-cta { flex-shrink: 0; }
    .nav-toggle {
      display: none; width: 44px; height: 44px; border: 0; background: transparent; padding: 10px;
    }
    .nav-toggle span {
      display: block; height: 2px; background: var(--char); margin: 6px 0; border-radius: 2px;
    }
    .drawer {
      position: fixed; inset: 0; background: rgb(28 25 23 / .55); z-index: 80; opacity: 0; visibility: hidden;
      transition: .2s;
    }
    .drawer.open { opacity: 1; visibility: visible; }
    .drawer-panel {
      position: absolute; right: 0; top: 0; bottom: 0; width: min(86vw, 360px);
      background: var(--paper); padding: 24px 20px; transform: translateX(100%); transition: .25s;
      display: flex; flex-direction: column; gap: 8px;
    }
    .drawer.open .drawer-panel { transform: none; }
    .drawer a {
      min-height: 44px; display: flex; align-items: center; padding: 0 12px; border-left: 3px solid transparent; color: var(--ink);
    }
    .drawer a.active { border-left-color: var(--ember); color: var(--ember); font-weight: 600; }
    .section { padding: 88px 0; }
    .section-alt { background: var(--smoke); }
    .section-head { margin-bottom: 36px; max-width: 760px; }
    .section-head h2 {
      font-size: 30px; line-height: 1.3; font-weight: 700; letter-spacing: -.03em; color: var(--char);
    }
    .section-head p { margin-top: 14px; color: var(--muted); }
    .kicker {
      display: inline-block; font-size: 12px; letter-spacing: .16em; text-transform: uppercase;
      color: var(--ember); font-weight: 600; margin-bottom: 10px;
    }
    .hero {
      position: relative; height: 90vh; min-height: 620px; overflow: hidden; background: var(--char); color: var(--inverse);
    }
    .hero-slide {
      position: absolute; inset: 0; opacity: 0; transition: opacity .7s ease; background-size: cover; background-position: center;
    }
    .hero-slide.is-on { opacity: 1; z-index: 1; }
    .hero-slide::before {
      content: ""; position: absolute; inset: 0;
      background: linear-gradient(105deg, rgb(28 25 23 / .88) 0%, rgb(28 25 23 / .55) 48%, rgb(28 25 23 / .28) 100%);
    }
    .hero-slide::after {
      content: ""; position: absolute; inset: 0; pointer-events: none; opacity: .12;
      background: repeating-linear-gradient(-28deg, transparent, transparent 10px, #C2410C 10px, #C2410C 11px);
    }
    .hero-copy {
      position: relative; z-index: 2; height: 100%;
      display: flex; flex-direction: column; justify-content: center; max-width: 720px; padding-top: 24px;
    }
    .hero h1, .hero .slide-title {
      font-size: 56px; line-height: 1.15; font-weight: 700; letter-spacing: -.04em;
    }
    .hero .slide-sub {
      margin-top: 18px; font-size: 18px; line-height: 1.7; color: #E7E5E4; max-width: 34em;
    }
    .hero-actions { display: flex; gap: 12px; margin-top: 28px; flex-wrap: wrap; }
    .hero-dots {
      position: absolute; z-index: 3; left: 50%; bottom: 28px; transform: translateX(-50%);
      display: flex; gap: 8px;
    }
    .hero-dots button {
      width: 28px; height: 4px; border: 0; border-radius: 2px; background: rgb(255 255 255 / .35); padding: 0;
    }
    .hero-dots button[aria-current="true"] { background: var(--gold); }
    .hero-arrow {
      position: absolute; top: 50%; z-index: 3; width: 44px; height: 44px; border: 1px solid rgb(255 255 255 / .35);
      background: rgb(28 25 23 / .35); color: #fff; border-radius: 6px; transform: translateY(-50%);
    }
    .hero-arrow.prev { left: 20px; }
    .hero-arrow.next { right: 20px; }
    .hero-arrow:hover { border-color: #fff; }
    .pain {
      padding: 36px 0; background: var(--smoke); border-bottom: 1px solid var(--line);
    }
    .pain-wrap {
      display: grid; grid-template-columns: 220px 1fr; gap: 28px; align-items: center;
    }
    .pain h2 { font-size: 22px; letter-spacing: -.02em; }
    .chips { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
    .chip {
      display: flex; gap: 10px; align-items: flex-start; background: #fff; border: 1px solid var(--line);
      border-radius: var(--radius); padding: 14px 14px 12px; min-height: 92px; box-shadow: var(--shadow-sm);
      transition: transform .2s, border-color .2s;
    }
    .chip:hover { transform: translateY(-3px); border-color: var(--ember); }
    .chip-ico {
      width: 28px; height: 28px; flex-shrink: 0; color: var(--ember);
    }
    .chip strong { display: block; font-size: 14px; }
    .chip span { display: block; font-size: 13px; color: var(--muted); line-height: 1.55; margin-top: 4px; }
    .split {
      display: grid; grid-template-columns: 1.05fr 1fr; gap: 48px; align-items: center;
    }
    .media {
      border-radius: 10px; overflow: hidden; box-shadow: var(--shadow-sm); border: 1px solid var(--line);
    }
    .media img { width: 100%; height: 100%; object-fit: cover; min-height: 420px; }
    .prose p + p { margin-top: .85em; }
    .prose p { color: var(--ink); }
    .badges { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 22px; }
    .badge {
      background: #fff; border: 1px solid var(--line); border-radius: 6px; padding: 8px 12px;
      font-size: 13px; color: var(--steel); font-weight: 600;
    }
    .badge b { color: var(--gold); margin-right: 6px; font-family: Inter, sans-serif; }
    .steps { position: relative; display: grid; grid-template-columns: repeat(5, 1fr); gap: 18px; }
    .steps::before {
      content: ""; position: absolute; left: 6%; right: 6%; top: 23px; height: 3px; background: var(--ember); opacity: .35;
    }
    .step { position: relative; }
    .step-num {
      width: 46px; height: 46px; border-radius: 50%; background: var(--gold); color: var(--char);
      display: grid; place-items: center; font-weight: 700; font-family: Inter, sans-serif; margin-bottom: 14px;
    }
    .step h3 { font-size: 17px; font-weight: 600; margin-bottom: 8px; }
    .step p { font-size: 14px; color: var(--muted); line-height: 1.65; }
    .grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
    .card {
      background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 22px;
      box-shadow: var(--shadow-sm); transition: transform .2s, border-color .2s, box-shadow .2s;
    }
    .card:hover { transform: translateY(-4px); border-color: var(--ember); box-shadow: var(--shadow-hover); }
    .card svg { color: var(--steel); margin-bottom: 12px; }
    .card h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; }
    .card p { font-size: 14.5px; color: var(--muted); line-height: 1.7; }
    .models {
      display: grid; grid-template-columns: 1.35fr 1fr; grid-template-rows: auto auto; gap: 20px;
    }
    .model {
      background: #fff; border: 1px solid var(--line); border-radius: 10px; overflow: hidden;
      box-shadow: var(--shadow-sm); display: flex; flex-direction: column;
    }
    .model-lg { grid-row: 1 / span 2; }
    .model img { width: 100%; height: 220px; object-fit: cover; }
    .model-lg img { height: 340px; }
    .model-body { padding: 20px 22px 22px; display: flex; flex-direction: column; gap: 10px; flex: 1; }
    .model h3 { font-size: 20px; }
    .params { font-size: 14px; color: var(--muted); }
    .params li { padding: 4px 0 4px 14px; position: relative; }
    .params li::before {
      content: ""; width: 6px; height: 6px; background: var(--ember); border-radius: 50%;
      position: absolute; left: 0; top: 11px;
    }
    .dark-case {
      background: var(--char); color: var(--inverse); position: relative; overflow: hidden;
    }
    .dark-case::before {
      content: ""; position: absolute; left: 0; top: 0; width: 4px; height: 100%; background: var(--ember);
    }
    .dark-case::after {
      content: ""; position: absolute; inset: 0; opacity: .08; pointer-events: none;
      background: repeating-linear-gradient(-32deg, transparent, transparent 12px, #C2410C 12px, #C2410C 13px);
    }
    .case-grid { display: grid; grid-template-columns: 1.1fr .9fr; gap: 40px; align-items: center; position: relative; z-index: 1; }
    .case-photos { display: grid; grid-template-columns: 1.2fr .8fr; gap: 12px; }
    .case-photos img { width: 100%; height: 100%; object-fit: cover; border-radius: 8px; min-height: 180px; }
    .case-photos img:first-child { min-height: 380px; grid-row: 1 / span 2; }
    .case-points li { padding: 16px 0; border-bottom: 1px solid rgb(255 255 255 / .12); }
    .case-points h3 { font-size: 18px; margin-bottom: 6px; }
    .case-points p { color: #D6D3D1; font-size: 15px; }
    .stats {
      background: #2A211C; color: #fff; padding: 56px 0;
    }
    .stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; text-align: left; }
    .stat-num {
      font-family: Inter, sans-serif; font-size: 48px; font-weight: 700; letter-spacing: -.04em; color: var(--gold); line-height: 1;
    }
    .stat-num small { font-size: 16px; margin-left: 4px; color: #E7E5E4; font-weight: 500; }
    .stat-label { margin-top: 10px; color: #D6D3D1; font-size: 14px; }
    .story-main {
      display: grid; grid-template-columns: .9fr 1.1fr; gap: 36px; align-items: center;
      background: #fff; border: 1px solid var(--line); border-radius: 10px; overflow: hidden;
    }
    .story-main img { width: 100%; height: 100%; min-height: 320px; object-fit: cover; }
    .story-main .txt { padding: 32px 32px 32px 8px; }
    .story-side { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-top: 20px; }
    .story-mini {
      background: #fff; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; box-shadow: var(--shadow-sm);
    }
    .story-mini img { height: 160px; width: 100%; object-fit: cover; }
    .story-mini .txt { padding: 16px 18px 20px; }
    .story-mini h3, .story-main h3 { font-size: 18px; margin: 8px 0; }
    .quotes { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
    .quote {
      background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 22px; box-shadow: var(--shadow-sm);
    }
    .avatar {
      width: 44px; height: 44px; border-radius: 8px; display: grid; place-items: center;
      background: var(--steel); color: #fff; font-weight: 700; font-family: Inter, sans-serif;
    }
    .quote-top { display: flex; gap: 12px; align-items: center; margin-bottom: 12px; }
    .stars { color: var(--gold); letter-spacing: 2px; font-size: 13px; }
    .tag {
      display: inline-block; font-size: 12px; padding: 2px 8px; border: 1px solid var(--line); border-radius: 4px; color: var(--steel);
    }
    .scene-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
    .scene {
      position: relative; min-height: 240px; border-radius: 10px; overflow: hidden; color: #fff;
    }
    .scene img { width: 100%; height: 100%; object-fit: cover; min-height: 240px; }
    .scene .cap {
      position: absolute; inset: auto 0 0 0; padding: 22px;
      background: linear-gradient(transparent, rgb(28 25 23 / .88));
    }
    .scene h3 { font-size: 20px; margin-bottom: 6px; }
    .scene p { font-size: 14px; color: #E7E5E4; }
    .scene .link { display: inline-block; margin-top: 8px; color: var(--gold); font-weight: 600; font-size: 14px; min-height: 44px; line-height: 44px; }
    .news-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
    .news { background: #fff; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; box-shadow: var(--shadow-sm); }
    .news img { height: 180px; width: 100%; object-fit: cover; }
    .news .txt { padding: 16px 18px 20px; }
    .news time { font-size: 12px; color: var(--muted); }
    .news h3 { font-size: 17px; margin: 6px 0 8px; }
    .more { margin-top: 22px; }
    .spec-table { width: 100%; border-collapse: collapse; background: #fff; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; }
    .spec-table th, .spec-table td { padding: 14px 16px; text-align: left; border-bottom: 1px solid var(--line); font-size: 15px; }
    .spec-table th { background: var(--steel); color: #fff; font-weight: 600; width: 28%; }
    .spec-table tr:last-child td, .spec-table tr:last-child th { border-bottom: 0; }
    .spec-table td { color: var(--ink); }
    .train-grid { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 18px; }
    .train-item {
      border-left: 3px solid var(--ember); background: #fff; padding: 18px 20px; border-radius: 0 10px 10px 0; border: 1px solid var(--line); border-left-width: 3px;
    }
    .faq-item { border: 1px solid var(--line); background: #fff; border-radius: 8px; margin-bottom: 10px; }
    .faq-item button {
      width: 100%; text-align: left; background: none; border: 0; min-height: 56px;
      padding: 14px 48px 14px 18px; font-size: 16px; font-weight: 600; position: relative; color: var(--char);
    }
    .faq-item button::after {
      content: "+"; position: absolute; right: 18px; top: 50%; transform: translateY(-50%); color: var(--ember); font-size: 22px;
    }
    .faq-item.open button::after { content: "−"; }
    .faq-item .ans { display: none; padding: 0 18px 16px; color: var(--muted); font-size: 15px; }
    .faq-item.open .ans { display: block; }
    .cta {
      background: var(--char); color: var(--inverse); position: relative;
    }
    .cta::before {
      content: ""; position: absolute; inset: 0; opacity: .1;
      background: repeating-linear-gradient(-28deg, transparent, transparent 11px, #C2410C 11px, #C2410C 12px);
    }
    .cta-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; position: relative; z-index: 1; align-items: start; }
    .trust li { padding: 10px 0 10px 28px; position: relative; color: #D6D3D1; }
    .trust li::before { content: "▣"; position: absolute; left: 0; color: var(--gold); }
    .form {
      background: #231F1C; border: 1px solid rgb(255 255 255 / .08); border-radius: 10px; padding: 24px;
    }
    .form label { display: block; font-size: 13px; margin-bottom: 6px; color: #E7E5E4; }
    .form .field { margin-bottom: 14px; }
    .form input, .form select, .form textarea {
      width: 100%; background: #1C1917; border: 1px solid #44403C; color: #fff;
      border-radius: 6px; min-height: 44px; padding: 10px 12px;
    }
    .form textarea { min-height: 96px; resize: vertical; }
    .form input.is-err, .form select.is-err, .form textarea.is-err { border-color: var(--ember); }
    .form-ok { display: none; background: rgb(212 160 23 / .15); color: #FDE68A; padding: 12px; border-radius: 6px; margin-top: 10px; }
    .form-ok.show { display: block; }
    .site-footer { background: #14110F; color: #A8A29A; padding: 56px 0 24px; font-size: 14px; }
    .foot-grid { display: grid; grid-template-columns: 1.4fr 1fr 1.2fr 1fr; gap: 28px; }
    .site-footer a { color: #D6D3D1; }
    .site-footer a:hover { color: var(--gold); }
    .site-footer h3 { color: #F5F5F4; font-size: 15px; margin-bottom: 12px; }
    .foot-brand { font-size: 18px; font-weight: 700; color: #fff; margin-bottom: 10px; }
    .legal { margin-top: 32px; padding-top: 18px; border-top: 1px solid #292524; display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; font-size: 13px; }
    .hex { fill: none; stroke: var(--ember); stroke-width: 2.2; }
    @media (max-width: 1280px) {
      .hero h1, .hero .slide-title { font-size: 48px; }
    }
    @media (max-width: 1024px) {
      .section { padding: 72px 0; }
      .hero h1, .hero .slide-title { font-size: 40px; }
      .pain-wrap, .split, .case-grid, .cta-grid, .story-main { grid-template-columns: 1fr; }
      .chips, .grid-3, .quotes, .news-grid, .train-grid, .stats-grid { grid-template-columns: repeat(2, 1fr); }
      .models { grid-template-columns: 1fr; }
      .model-lg { grid-row: auto; }
      .nav-links, .nav-cta { display: none; }
      .nav-toggle { display: inline-block; }
      .steps { grid-template-columns: 1fr; }
      .steps::before { left: 22px; right: auto; top: 0; bottom: 0; width: 3px; height: auto; }
      .foot-grid { grid-template-columns: 1fr 1fr; }
      .story-main .txt { padding: 22px; }
    }
    @media (max-width: 768px) {
      .hero { height: 88vh; min-height: 560px; }
      .hero h1, .hero .slide-title { font-size: 40px; }
      .section { padding: 52px 0; }
      .section-head h2 { font-size: 26px; }
      .chips, .grid-3, .quotes, .news-grid, .scene-grid, .story-side, .train-grid, .stats-grid { grid-template-columns: 1fr; }
      .hero-arrow { display: none; }
      .topbar-right { display: none; }
      .pain-wrap { grid-template-columns: 1fr; }
      .media img, .model img, .model-lg img { min-height: 220px; height: 240px; }
      .spec-table, .spec-table tbody, .spec-table tr, .spec-table th, .spec-table td { display: block; width: 100%; }
      .spec-table th { width: 100%; }
      .spec-table td { border-bottom: 1px solid var(--line); margin-bottom: 8px; }
      .legal { flex-direction: column; }
    }
    @media (max-width: 520px) {
      .container { width: min(100% - 28px, var(--container)); }
      .hero h1, .hero .slide-title { font-size: 32px; }
      .btn { width: 100%; }
      .hero-actions { flex-direction: column; }
      .stat-num { font-size: 36px; }
    }
    @media (prefers-reduced-motion: reduce) {
      html { scroll-behavior: auto; }
      *, *::before, *::after { animation: none !important; transition: none !important; }
    }